1. Field of the Invention
The present invention relates to a numerical controller, and particularly, to a numerical controller with a function of preventing an operator from erroneously inputting tool offset data.
2. Description of the Related Art
When a machine tool is operated by a control of a numerical controller, it is necessary to input an offset value as data relating to a tool used for machining before executing a machining program. The numerical controller decides a tool path or performs an interference check on the basis of the data relating to the tool and the machining program.
When an operator inputs data relating to a tool, a decimal point is omitted or an erroneous offset value is input due to a mistake in operating a key in some cases. In these cases, since the numerical controller decides a tool path on the basis of the erroneous correction amount, the tool is controlled along the tool path different from what the operator supposes, and thus there is a concern that the tool interferes with and damages a workpiece, a table, a jig, or the like.
Heretofore, to solve this problem, functions of preventing erroneous operation of an operator at the time of input are introduced. One among them, for example, JP 2009-080621 A discloses a function of setting a range of inputtable values in advance and alerting an operator when a value outside the range is input (FIG. 5).
In addition, it is considered that the problem is solved in such a manner that a result of erroneous input can be recognized on the spot by drawing an image according to the input data.
However, in the method of setting an inputtable range in advance as in JP 2009-080621 A, it is necessary that dedicated information is set in advance and the operator calculates the range.
In addition, in the case of displaying an image of a tool and an offset amount by drawing, a plurality of tools have to be displayed side by side in order that the operator can make a determination at a glance, and thus since it is necessary to widen an area in which tools are displayed side by side, there is a problem that the number of pieces of data which can be displayed at one time is decreased.